Thanks CooperMan, I thought that might be the case. Worth noting that my replacement from mevspares has usable innards in a pinch. Actually, if I'd had a fitting for the spur, the part would have fitted fine. It cost £34.50 including postage.
"DOT" 35th Anniversary Edition Plus 8- family owned from new. Rolls Royce Pewter. 06 Saab 93